1. Technical Field.
This invention relates to a bladder drainage cycler and method of use. It is a hospital instrument for draining urine from bladders of patients automatically, thoroughly and antiseptically when necessary to bypass natural bladder drainage.
2. Background Information
Hospital instruments and procedures for draining bladders of patients has evolved from constant uncycled drainage through siphoning, suction and various types of cyclic methods. Fundamental to an effective instrument and method is allowing the bladder to fill reasonably and then draining it without a suction effect and without allowing build-up or entry of infectious contaminants in the drainage system.
Included in previous methods have been U.S. Pat. Nos. 2,602,448 and 2,860,636 which utilized a siphon in combination with a reservoir to provide cycle draining of the bladder. Pressure release in these is controlled by raising the height of the device on a bedside tree. It is subject to distortion by shifting and turning of the patient and therefore, very undependable in addition to being restrictive of the patient.
In U.S. Pat. No. 3,598,124, a siphon leg is controlled by merely attaching a catheter to a bedside tree at predetermined adjusted height, which varies the pressure at which the bladder will drain and provides a flutter valve near the patient to break the siphon action of the system once the bladder has drained. In U.S. Pat. No. 4,230,102, a device for the draining of a bladder is shown in which a T-joint has been placed on a catheter and has a pressure membrane attached thereto in a large casing for actuating a pressure switch which in turn actuates an electric motor driving a gear train and cam. A cam follower is spring loaded to clam the catheter for two minute cycles upon actuation by the pressure switch to drain the bladder. This type of device, however, is expensive and bulky and positions an electrical apparatus adjacent to the catheter. In U.S. Pat. No. 4,424,058, a spring-return valve is provided in conjunction with a siphon-release orifice to prevent excessive suction and to prevent urine from remaining in the system after drainage. A problem with this system was that resiliency of the spring increased with distance of travel from a closed position. This tended to cause some fluid to remain in the bladder because only a full bladder would open it and only a relatively full bladder would keep it open to allow complete drainage unless overridden by the patient. Also, positioning of tubes leading from it were parallel to the leg on which it was attached and provided a situation for retention of fluid in the system.
This invention provides magnetic closing of a valve member with decreased rather than increased closing pressure when opened. As the bladder is emptied, decreasing head pressure against the valve, therefore, can keep the valve open for more complete drainage than can be provided by a resiliency-operated valve.
Valve-closing pressure decreases as a result of three factors: (1) magnetic pull of a valve decreases as its open distance from magnetic attraction in the direction of a valve seat increases, (2) fluid passing through the system provides a partial insulation which tends to decrease magnetic attraction between magnetic members, and (3) an optional spring in one of the embodiments of the invention causes the magnetic members to be further apart when the valve opens. In addition, one of the embodiments of the invention provides convenient manual override to decrease or eliminate totally the magnetic closing pressure of the valve.